I don't understand all the complaints about the weight and size, and price.
If you want a lighter weight 45mm-50mm lens, the Olympus M.Zuiko 45/1.8 or Panasonic-Leica Macro-Elmarit 45mm f/2.8 ASPH are both available. The Nocticron-DG 45/1.2 ASPH is all metal construction, has OIS, and is quite a bit faster than either: of course it's going to be larger, weigh more, and be more expensive.
It's not like there are no choices. Look at even available 50mm f/1.2 lenses from other manufacturers... They're all in and around this size and weight class, plus or minus a few grams, depending upon construction materials.
The Olympus M.Zuiko 75/1.8 is similar in size and weight. It's handy and comfortable to use on the E-M1 body sans grip, a little large on the much more compact E-PL1 body. I see the Nocticron as being in the same class, a mite heavier and larger due to the OIS and all-metal construction.